Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GI 2 > Physiology > Flashcards

Physiology Flashcards

1
Q

“gastric receptive relaxation reflex” is another name for this

A

vaso-vagal reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

sensory ganglion of CN-X

A

nodose ganglion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

where the afferent & efferent roots of CN-X meet in the brainstem

A

nucleus tractus solitarius (NTS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Locations and functions of the submucosal and myenteric plexuses

A

submucosal = between submucosa and circular muscle (shallower); SENSES LUMEN ENVIRONMENT

myenteric = between circular and longitudinal muscle (deeper); REGULATES CONTRACTION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Primary PSNS and SNS neurotransmitters in the gut

A

PSNS: ACh
SNS: ACh (pre-ganglionic) and NE (post-ganglionic)

  • Any part of the SNS that’s in the GI tract is post-ganglionic and therefore NE
  • In the GI tract: both pre- and post-ganglionic PSNS; only post-ganglionic SNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which of these are paracrine peptides rather than endocrine hormones?

Gastrin
CCK
Histamine
Secreting
Somatostatin
GIP
A

Histamine

Somatostatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is the excretion of paracrine peptides different from that of endocrine hormones?

A 
Hormones = secretory granulation
Peptides = local diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where are G cells and what do they secrete?

A

Stomach; gastrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where are I cells and what do they secrete?

A

Duodenum/jejunum; CCK

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where are S cells and what do they secrete?

A

Duodenum; Secretin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which organs secrete GIP?

A

Duodenum/jejunum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does Gastrin target and what does it do?

A

Target: Stomach and Small Intestine

Action: + HCl & Pepsinogen; +Peristalsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does Secretin target and what does it do?

A

Target: Pancreas

Action: + alkaline digestive proenzymes (bicarb) – Peristalsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does CCK target and what does it do?

A

Target: Pancreas & Gallbladder

Action: + bile secretion (relaxation of sphincter of Oddi) and + digestive proenzymes

+ gastric distensibility and - stomach contraction (wants to keep food in the stomach)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does GIP target and what does it do?

A

Target: Pancreas & Stomach

Action: + insulin; - peristalsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does VIP do?

A

It is an inhibitory PSNS neurotransmitter (inhibit ACh); decreases constriction of sphincters; increases relaxation; slows everything down so that it can regulate electrolyte fluid balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Effect of ACh and NE on saliva

A

Both increase!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does GRP do?

A

Increase Gastrin (So increase HCl + Pepsinogen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What do Enkephalins do?

A

Inhibit ACh release; inhibits GI motility (opioids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does Neuropeptide Y do?

A

Makes you hungry; relaxes smooth muscle and decreases intestinal secretions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does Substance P do?

A

Induces vomiting; contracts smooth muscle

ALWAYS GO WITH ACH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the difference between tonic and phasic contractions?

A 
Tonic = constitutively contract without AP input ("below the AP threshold")
Phasic = only contract sometimes; require AP's
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the relationship between a slow wave and an AP?

A

Slow waves are below the AP threshold; slow waves still involve depolarization and repolarization of the membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which cell type stimulates slow waves?

A

ICC’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which part of the brain contains the swallowing center?

A

Medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which cranial nerves carry afferent input about swallowing?

A

CN-9 and 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Which phases of swallowing are under voluntary control?

A

Only the oral phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The esophageal phase of swallowing is controlled by both the brainstem swallowing reflex and cells of the ENS. What is the difference between primary and secondary peristaltic waves in swallowing?

A

Primary – controlled by the medulla. CANNOT OCCUR IF YOU HAVE NO VAGUS NERVE.

Secondary – controlled by the ENS; occur if primary waves don’t clear the esophagus; independent of oral and pharyngeal phases; CAN OCCUR AFTER VAGOTOMY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Describe the pressure differential in the esophagus that occurs with swallowing.

A

Sphincters = negative pressure when you swallow (they relax and the food gets sucked through)

Length of the esophagus = positive pressure when you swallow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How much of the esophagus is striated (not smooth) muscle?

A

The upper 1/3 (including and past the UES)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Which hormone upregulates the MMC? What does the MMC do?

A

Hormone; Motilin (small intestine)

Function: periodic bursting contractions in the stomach q 90 minutes during fasting; they keep food residue from building up in the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Which hormone increases gastric distensibility and decreases gastric contraction (keeps food in the stomach)

A

CCK

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Effect on the rate of gastric emptying:

decreased distensibility of the orad

A

Increases rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Effect on the rate of gastric emptying:

Increased tone of the pylorus

A

Decreases rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Effect on the rate of gastric emptying:

Decreased force of peristalsis in the antrum

A

Decreases rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Effect on the rate of gastric emptying:

Increased diameter and inhibition of segmenting contractions in the proximal duodenum

A

Increases rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How long does gastric emptying take?

A

3 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the effect of stimulating the entero-gastric reflex?

A

Decreases rate of gastric emptying (negative feedback from the duodenum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the function of a segmenting contraction?

A

To grind up food; the predominant contraction type in the intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Which muscle types are most important in peristaltic vs segmenting contractions?

A

Peristaltic – longitudinal

Segmenting – circular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What do ECC’s (entero-chromaffin cells) do?

A

Secrete 5-HT at IPANs (intrinsic primary afferent neurons); initiate peristalsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Effect of 5HT on intestinal contractility

A

+++

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Effect of PG’s on intestinal contractility

A

+++

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Effect of insulin on intestinal contractility

A

+++

45
Q

Effect of secretin on intestinal contractility

A
46
Q

Effect of glucagon on intestinal contractility

A
47
Q

Describe the pressure gradient of the internal and external sphincters of the rectum prior to defecation (the rectosphincteric reflex)

A

IS: negative (relaxed)
ES: positive (contracted) – “holding it”

48
Q

What happens to the defecation reflex of a patient with a lower spinal cord injury?

A

Loss of voluntary control (I think the rectosphincteric reflex is still intact)

49
Q

A deficiency of which neurotransmitter is associated with achalasia? Why?

A

VIP – decreased relaxation of LES

50
Q

Destruction of the ENS at the LES would lead to which consequence?

A

Achalasia

51
Q

Destruction of the vagus nerve related to diabetes would lead to which consequence?

A

Gastroparesis

52
Q

Hirschsprung disease presents with a deficiency of which neurotransmitter?

A

VIP (since it lives in ganglion cells)

53
Q

Tonicity of saliva versus plasma: how is the chemical content different?

A

Hypotonic

HIGHER K/HCO3 (secreted)
LOWER NaCl (absorbed)
54
Q

What are the different functions of ductal and acinar cells in saliva production?

A

Acinar: make the saliva
Ductal: regulate ion concentration (net absorption)

55
Q

Which types of GPCR’s regulate PSNS and SNS effects on saliva production?

A

PSNS = Gq (IP3)

SNS = Gs (cAMP)

*Both increase saliva

56
Q

Which spinal levels control SNS saliva production?

A

T1-T3

57
Q

What effect do Vasopressin & Aldosterone have on saliva?

A

– NaCl (saving it for the rest of the body)

++ K/HCO3

58
Q

What are the differences in location and function of the pyloric and oxyntic glands?

A

Pyloric = antrum; secretes gastrin

Oxyntic = fundus & proximal body; secretes HCl

59
Q

What do chief cells secrete?

A

Pepsinogen

60
Q

What happens to gastrin secretion at low stomach pH?

A

It is decreased –> less HCl produced (negative feedback)

61
Q

What does histamine do in the Gi tract?

A

Potentiates ACh and Gastrin

62
Q

Giving Atropine (a PSNS blocker) can decrease stomach acid, but it’s not a great treatment. Why?

(*Hint: what are the NT’s used by parietal vs G cells?)

A

Atropine blocks the direct pathway of HCl secretion (blocks parietal cells from secreting acid).

HOWEVER: it has no effect on G cells (gastrin secretion). This is because the NT at G cells is GRP, not ACh.

63
Q

Which 2 stomach cell types are directly stimulated by the vagus nerve? What are the NT’s used?

A 
Parietal Cells (ACh)
G cells (GRP)
64
Q

What do D cells do?

A

Secrete somatostatin

65
Q

What are the 2 immediate effects of a gastrinoma (ZES)?

A

+ HCl secretion

+ Parietal cell mass (trophic effect)

66
Q

Clinical presentation of ZES

A

Duodenal ulcers with steathorrhea

67
Q

Why does ZES cause steathorrhea?

A

Low duodenal pH is a stimulant for pancreatic lipases

68
Q

Where are gastrinomas (ZES) located?

A

Pancreas

69
Q

Effect of H. pylori on HCl levels

A

DECREASE

70
Q

Effect of H. pylori on Gastrin levels

A

INCREASE

71
Q

Effect of a duodenal ulcer (any type) on HCl levels

A

INCREASE (drastic in ZE)

72
Q

Effect of a duodenal ulcer (any type) on Gastrin levels

A

INCREASE (drastic in ZE)

73
Q

What are the functions of acinar and ductal cells in the pancreas?

A

Acinar – secrete enzymes

Ductal – secrete aqueous HCO3

74
Q

What is the tonicity of pancreatic fluid vs. plasma?

A

Isotonic (HCO3 secreted = H absorbed)

75
Q

What happens in the 3 phases of pancreatic secretion?
1- cephalic
2- gastric
3- intestinal

A

cephalic - initiated by smell and taste; enzymatic secretion (CN-X)

gastric - initiated by stomach distention; enzymatic secretion (CN-X)

intestinal - 80% of all pancreatic secretions! Both enzymatic and aqueous

76
Q

Which GPCR’s are involved in pancreatic enzyme vs aqueous solution secretion?

A

Enzymes = I cell –> CCK –> Gq

Aqueous = S cell –> Secretin –> Gs (cAMP)

77
Q

How does CF lead to pancreatitis?

A

No HCO3 secretion in intestinal phase = no secretion mechanism for digestive enzymes either

78
Q

BSEP and MRP-2 both require ATP. In which step of bile synthesis are they involved?

A

Gallbladder contraction & relaxation of sphincter of Oddi

79
Q

ASBT is a transporter on enterocytes. In which step of bile acid metabolism is it involved?

A

Absorption of bile salts into portal circulation by the intestines

80
Q

NTCP and OATP are both transporters that are involved in re-uptake of recycled bile acids back to the liver. What is the difference between them?

A 
NTCP = sodium dependent
OATP = sodium independent
81
Q

Many parts of the Gi tract participate in passive reuptake of recycled bile acid. Which is the only part with active transporters (ASBT’s)?

A

Ileum

82
Q

How much bile acid is recycled?

A

90%

83
Q

What effect does an ileal resection have on bile secretion from the intestine?

A

Greatly decreased, since most active reuptake of bile occurs in the ileum

84
Q

What effect does SIBO (small intestine bacterial overgrowth) have on bile secretion from the intestine?

A

Greatly decreased; bacterial can steal bile and eat it; risk factor = high GI pH

85
Q

Which enzyme is decreased in physiologic jaundice of the newborn?

A

UDP glucoronyl transferase

86
Q

Which type of jaundice is caused by anemia?

A

Unconjugated (back-up)

87
Q

Which 2 conditions cause conjugated jaundice?

A

Dubin-Johnson

Rotor

88
Q

Which type of jaundice is caused by CHF?

A

Unconjugated (back up)

89
Q

What are the Folds of Kerckring and what do they do?

A

Longitudinal folds that increase the SA of the intestine (get shorter as you move through the SI)

90
Q

Which intestinal cell type is damaged in chemotherapy?

A

Enterocytes

91
Q

What do Paneth cells do?

A

Secrete immune cells in the intestine

92
Q

Which 2 macronutrients are digested in the mouth?

A

Carbs & fats

93
Q

What are the 3 end products of carbohydrate metabolism?

A

1- glucose
2- galactose
3- fructose

94
Q

Which form of carbohydrates can be absorbed by enterocytes?

A

Monosaccharides only

95
Q

Which two transporters bring monosaccharides into the enterocyte? Which one brings them into the blood?

A

Apical/luminal = SGLT (glu/gal –2ry active) & GLUT 5 (fru)

Basolateral = GLUT 2 only

96
Q

Which enzymes break trypsinogen into trypsin? Where?

A

Enteropeptidase in the SI or

Trypsin in the SI

97
Q

Where are most proteins absorbed in the Gi tract?

A

SI

98
Q

Do amino acids all share the same transporters?

A

No. On both membranes there are 4 different ones (based on charge)

99
Q

2 products of trigylceride metabolism

A

1- monoglyceride

2- fatty acid

100
Q

2 products of cholesterol ester metabolism

A

1- cholesterol

2- fatty acid

101
Q

2 products of phospholipid metabolism

A

1- fatty acid

2- lysolecithin

102
Q

How are lipids transported into the blood?

A

As chylomicrons

103
Q

Which pathological condition is caused by a deficiency of ApoB, leading to improper chylomicron formation?

A

Abetalipoproteinemia

104
Q

B12 metabolism begins with parietal cells in the fundus of the stomach. Where does it end?

A

Terminal ileum

105
Q

Autoimmune gastritis causes B12 anemia. What’s another cause of it?

A

Atrophic gastritis

106
Q

Na-dependent transporters facilitate absorption of these macros in the small intestine

A

Water soluble vitamins

107
Q

The vast majority of electrolyte absorption occurs here

A

Small intestine

108
Q

Which 2 electrolytes are secreted in the colon?

A

1- bicarb

2- potassium

GI 2 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions